As the light-emitting material having phosphorescence in visible region used for a light emitting layer of light-emitting device, devices using a metal complex (hereafter may be referred to as triplet light-emitting complex) showing light emission from triplet excited state have been known.
As the triplet light-emitting complex, for example, Ir (ppy)3 which includes iridium as the central metal, (Appl. Phys. Lett., 75, 4 (1999)), PtOEP which includes platinum as the central metal (Nature, 395, 151 (1998)), Eu(TTA)3-phen which includes europium as the central metal (Jpn. J. Appl. Phys., 34, 1883 (1995)) are known.

However, for forming a light emitting layer using the above well-known triplet light-emitting complexes, only the methods, such as vacuum-depositing method, are applicable, and it has been difficult to form a light emitting layer by coating method.